THE TESTICLE AND THE OVARY 365 



which during oestrus is so plainly manifested in the display 

 of sexual feeling. 



THE FUNCTION OF THE CORPUS LUTEUM 



Various theories have been put forward to explain the formation 

 and presence of the corpus luteum. According to one view, which was 

 taught until recently, the development of this structure was merely 

 a result of the excessive vascularisation which characterises the 

 entire internal generative tract during the period of pregnancy. Very 

 little consideration of the actual facts is needed to convince one of 

 the inadequacy of this explanation. The blood supply to the 

 generative organs is greatest during the later stages of pregnancy, 

 when the corpus luteum is becoming diminished in size. Moreover, 

 the rapid hypertrophy of the luteal cells takes place independently 

 of pregnancy during the very early stages of development at a 

 time when there is no appreciable congestion of the genital 

 organs. According to another theory, the corpus luteum was of 

 the nature of a stop-gap, whose purpose was to preserve the cortical 

 circulation of the ovary by preventing an excessive formation of 

 scar-tissue. 1 



Prenant 2 seems to have been the first to suggest that the corpus 

 luteum was a ductless gland. He supposed it to produce an internal 

 secretion which exercised an influence over the general metabolism 

 in the manner attributed to the internal ovarian secretion. The 

 phenomenon of chlorosis was explained as being due to the absence 

 of this secretion. Prenant supposed also that the corpus lutoum bad 

 the further function of preventing ovulation during pregnancy or 

 between the oestrous periods. 



This theory was supported by Re'gaud and Policard, 3 who stated 

 that, by means of special methods of staining, droplets of a secretory 

 substance could be detected in the cells of the corpus luteum of tbe 

 hedgehog. 



Beard 4 independently suggested that the corpus luteum is ;i 

 contrivance to suppress ovulation during pregnancy, while he supposed 

 it to degenerate before parturition in order to admit of ovulatin 

 occurring immediately afterwards. It must be pnintrd out, however, 

 that in many Mammals, if not in the majority, the breeding season 



1 Clark, "Ursprung, Wachstuin, und Ende des Corpus Luteum," .!><//. f. 

 Aunt. u. Phys., Anat. Abth., 1898. Whitridge Williams, til.xtrt ,-;,-*, New York, 

 1903. 



2 Prenant, "La Valeur Morphologique du Corps Jaune," /ter. <:?n. des 

 Sciences, 1898. 



3 Regaud and Policard, "Fonction Crlandulaire de 1'Epithelium Ovan<]in- 

 chez la Chienne," C. R. de. Soc. de TiioL, vol. liii., 1901. 



4 Beard, The Span of Gestation and the Cav*e of Rirth, Jena, 1897. 



